Coating metals



CHRISTIAN DANTSIZEN, F SCHENECTADY, NEW YORK,

ASSIGNOR TO GENER ELECTRIC COMPANY, A CORPORATION .OF NEW YORK.

coe'rrne METALS.

No Drawing.

- To all whom it may-concern 7 Be it known that I, CHRISTIAN DANT'SIZEN,a citizen of-the United States, residing at Schenectady, in the countyof Schenectady, State of New York, have-invented certain new and usefulImprovementsin Coating Metals, of which the following is aspecification. r

The present invention relates to the surface alloyage of one metalwithanother metal, as, for example, the surface. alloyage of iron orcopperwith another metal, for example, aluminum.

The present invention comprises a modifiecl process of carrying out thetreatment of metals described in U. S. Patents 1,155,974: to Van Aller,and 1,091,057 to Gilson, one of the main objects of which is to renderthe treated surface inoxidizable. The procedure described in thesepatents involves the heating of the metal on which surface alloyage isdesired in the presence of a metal powder.

In accordance with my .present invention .the product described in thesepatents is produced by a process involving the use of a molten treatingmetal in the presence of an alloying metal, It is the object of myinvention to reduce the equipment needed and reduce the time requiredfor producing the desired article. i

The following process for treating metals such as iron, copper or thelike, with aluminum, is illustrative of my invention. The metal articleto be treated, for example, iron, which for the sake of convenience willbe called the foundation metal is first thoroughly cleaned, preferablyby pickling for about five minutes in hydrochloric acid solution of aspecific gravity of 1.1 and then is placed for about a minute inaconcentrated solution of zinc chlorid.

While still wet with zinc chlorid the cleaned foundation metal isbrought into contact with an easily fusible metal capable of alloyingwith both the foundation metal and the treating metal. -Metals suitablefor this purpose are zinc andtin. The foundation metal may be allowed toremain in contact with molten tin at a temperature of 300 C. for aboutfifteen seconds.

The foundation metal after being with drawn from the tin bath is broughtinto contact with the treating metal, for ex-' ample, aluminum. Forexample, the foundation metal after being subjected to the Specificationof Letters Patent.

Patented June, '7, feet.

Application filed November 1, 1919. Serial No. 335,090.

U bath may be introduced into a bath consisting of one part of tin and 8to 8 parts of aluminum by weight. This bath p'refen' ably should have atemperature of about 800 C. After having been left in contact with thealloy of aluminum for about 30 tin seconds, the foundation metal isheated to a.

temperature suiiiciently high to cause penetration and alloyage of thealuminum into the surface layer of the foundation metal. Preferably thefoundation metal is vigorously shaken conveniently in an iron box forabout 15 seconds to remove adherent metal before being thus heated. Thefinal firing temperature will depend upon the character of the metals tobe alloyed and other conditons, but when working with a foundation metalof iron to be treated with aluminum I have found firing at a termperature of about 800 C. for about fifteen minutes to be satisfactory.

While I have described the preferred method of carrying out myinvention, I wish it to be understood that various modifications may bemade therein without departing from the spirit of my invention.

In some cases the preliminary treatment in a bath of tin, zinc or othermetal alloyng with the foundation metal and the treatmg metal may beomitted, the foundation. metalbeing subjected only to a molten bath ofalloy of the treating metal and an easily fusible metal, for example, abath of aluminum and tin. Somewhat better results however are obtainedby the use of an intermediate bath of tin, zinc or the like.

Instead of a chemical pickling to cleanse the surface of the metal,sandblasting may be used with good effect prior to applying the alloyingmetals.

What I- claim as new and desire to secure by Letters Patent of theUnited States, is

1. The process of treating metals to render them inoxidizable at hightemperatures which consists in thoroughly cleaning the surfaces of thearticle to be treated, coat ing the surface with metal'having arelatively low fusing point, then dipping 111 molten aluminum and firingat a relatively high temperature.

2. The prOcesSof'treating metals to ren- 5 der them inoxidizable at hightemperatures which consists in pickling the article in acid, coating thecleaned surfacewith metal having a relatively low fusing point in thepresence of a flux, then dipping in molten aluminum and firing at atemperature high enough to cause alloyage of aluminum with said metalarticle.

3. The process of treating metals to render them inoxidizable at hightemperatures which consists in coating a clean surface of the articlewith tin, then dipping in molten aluminum and firing at about 800 C.

4. The process of treatlng metals to render them inoxidizable at hlghtemperatures which consists in treating the article with a picklingsolution, coating the surface with tin, then dipping in molten mixtureof aluminum and tin and firing at about 800 C. 5. The process ofalloying a foundation metal upon its surface with a second metal whichconsists in bringing said foundation metal in a clean state into contactwith a second metal to be alloyed therewith in the presence of a thirdeasily fusible metal capable of alloying with both of said metals andthen heating the foundation metal while in contact with said metals to atemperature sufiiciently high to cause said second metal to penetratethe surface of said foundation metal and alloy therewitht 6. The processof treating metals to render them inoxidizable at high temperature whichconsists in bringing a clean surface of a foundation metal article to betreated 111to contact with a molten metal readily alloyable both withsaid metal and with aluminum, then bringing aluminum in contact withsaid surface and finally firing at a temperature sufficiently high topromote alloyage between said foundation metal and aluminum.

7. The process of alloying a foundation metal of iron or the like withaluminum which consists in coating clean surface of said foundationmetal with tin, then coating the tinned surface with aluminum andfinally firing said coated metal at a temperature high enough to causealloyage of aluminum with said foundation meta 8. The process oftreating metals to render them inoxidizable at high temperature, whichconsists im bringing the metal to be treated in a clean condition intocontact with molten aluminum in the presence of a material causing thealuminum to wet the surface of said metal and then firing the coatedarticle at a temperature sufficiently high to cause alloyage of thealuminum with said metal.

In witness whereof, I have hereunto set my hand this 31st day ofOctober, 1919.

CHRISTIAN DANTSIZEN.

